IANAL, but as I understand the law, the 'service provider' who registers is the one who is protected. Posterous is providing you and anyone who comments on you

IANAL, but as I understand the law, the 'service provider' who registers is the one who is protected. Posterous is providing you and anyone who comments on your blog a service - they can register to protect themselves. You are providing a service by providing stories and allowing people to comment. Theoretically, without any safe harbour, either you or Posterous could be found to be contributorily liable for copyright infringement in a comment on your blog, since you both provided services which allowed the infringement to occur. So to answer your questions: 1 - Posterous has registered an agent, to protect themselves, and you might want to register to protect yourself. 2 - You both are potentially Service Providers. 3 - You can designate an agent (which could be you), and Posterous' designated agent on the form they have put in is Sachin Agarwal. If you are worried, I'd suggest talking to a lawyer with expertise in Copyright law.